Method of treating spun yarns in the course of their manufacture



Patented Nov. 20, 1928.

UNITED STATES- PATENT OFFICE.

JAMES J'. BOYLE, OI! NEW YORK MILLS, NEW YORK.

METHOD OF TREATING SPUN YARNS IN THE COURSE OF THEIR MANUFACTURE.

No Drawing.

The present invention relates broadly to new and useful improvements inthe method of treating spun yarns in the course of their manufacture.

The invention hasparticular relation to the treatment of yarns whichhave been spun from relatively short lengths of rayon or other similarartificial fibers or filaments.

When a yarnis spun, as, for instance, on

regular cotton spinning machinery, from relatively short lengths ofrayon, a substantial loss is to be noted in the luster of the yarn ascompared with the luster which existed in the rayon filaments or fibersbefore they were spun.

The principal object of the present invention is to provide a methodwhereby the original luster of the rayon fibers or filaments may besubstantially restored in the finished spun yarn.

In spinning the relatively short rayon fibers or filaments on cottonmachinery, it is necessary, of course, as in cotton yarn manufacture, toimpart a substantial twist to the yarn in order that the fiberscomposing it may be properly interlaced and the yarn thereby given therequired strength. It is frequent practice, for instance, to put in afinished No. 20 cotton yarn a twist of seventeen turns to the inch.

It has been found that the rayon filaments or fibers thus twisted orspun together produce a yarn possessing substantially less luster orsheen than that found in a mass of the same short-length rayon fibersbefore they were spun and twisted together. This result is apparentlydue to the following dissimilar conditions: The sheen or luster to benoted in rayon in its original state results in large 40 measure fromthe fact that the fibers are relatively straight and are arranged ingroups wherein each individual fiber is parallel to the other fibersofthe group. An unbroken.

reflecting surface of relatively large area thus exists and thesheen orluster apparent is consequently of substantial degree. But when therayon fibers-are twisted together by the spinning process, thisparallelism is substantially reduced and the fibers intertwined andcrossedso that the surface of the yarn is broken up and, consequently,at no point does a smooth reflecting surface exist in anything like thedegree found in the original state of the rayon fibers and filaments.

Application filed August 27, 1926. Serial No. 132,032.

I have discovered, however, that this original parallelism and therelatively unbroken reflecting surface produced thereby can besubstantially restored if after the yarn has been passed completelythrough the spinning operation, it is then subjected to a reversetwisting process. Hence, the method of the present invention consists inspinning the yarn and twisting it in the spinning machinery andsubsequently gving it a reverse twist under slight tension. Apparently,this reverse twisting under slight tension causes the individual fibersto approach their original parallelism sufficiently to largely restorethe sheen or luster.

The extent to which the reverse twisting is done is, of course,dependent upon the size of the yarn being produced, the tensile strengthrequired of the particular yarn for the particular use to which it is tobe put, and a number of other practical commercial considerations.

In general, it may be said that the reverse twisting should not reducethe original number of twists per inch bymore than thirtythree andone-third per cent, although this is not an absolute limit. 7

It is found that while the reverse twisting alone will substantiallyimprove the luster of the yarn, even greater improvements can generallybe effected if the yarn is moistened and the reverse'twisting done whilethe yarn is in the moistened condition.

It should be mentioned that the yarn when thus subjected to reversetwisting is not in its wet state as strong as .it was before the reversetwisting was done, but that in a dry condition it is stronger thanformerly.

My experiments and trials to date indicate that the reverse twistingprocess is desirable and commercially usable only where it is desired-tohave a soft, lustrous yarn and where it is not required that the yarn bepossessed of great tensile strength.

What I claim is: y Y

1. The method of treating spun rayon yarns which consists in subjectingthe yarn in the presence of moisture to a reverse twisting after theyarn has been completely spun to thereby improve the luster.

2. The method of treating spun rayon yarn which consists in iving theyarn a relatively high twist and su sequently giving the yarn a reversetwist-to reduce in the finished prodnot the number of twists per'inchoriginally existing, whereby the luster of the yarn is improved.

3. The method of treating spun rayon yarns which consists in moisteningthe yarn 6 and then subjecting it to a reverse twisting after the yarnhas been completely spun.

4. The method of treating spun rayon yarn which consists in giving theyarn a relatively high twist and subsequently moistening it and thengiving it a reverse twist to reduce in the finished product the numberof twists per inch originally existing, whereby the luster of the yarnis improved.

In testimony whereof I afiix my signature.

JAMES J. BOYLE.

